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Proceedings Paper

In vivo performance of photovoltaic subretinal prosthesis
Author(s): Yossi Mandel; George Goetz; Daniel Lavinsky; Phil Huie; Keith Mathieson; Lele Wang; Theodore Kamins; Richard Manivanh; James Harris; Daniel Palanker
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Paper Abstract

We have developed a photovoltaic retinal prosthesis, in which camera-captured images are projected onto the retina using pulsed near-IR light. Each pixel in the subretinal implant directly converts pulsed light into local electric current to stimulate the nearby inner retinal neurons. 30 μm-thick implants with pixel sizes of 280, 140 and 70 μm were successfully implanted in the subretinal space of wild type (WT, Long-Evans) and degenerate (Royal College of Surgeons, RCS) rats. Optical Coherence Tomography and fluorescein angiography demonstrated normal retinal thickness and healthy vasculature above the implants upon 6 months follow-up. Stimulation with NIR pulses over the implant elicited robust visual evoked potentials (VEP) at safe irradiance levels. Thresholds increased with decreasing pulse duration and pixel size: with 10 ms pulses it went from 0.5 mW/mm2 on 280 μm pixels to 1.1 mW/mm2 on 140 μm pixels, to 2.1 mW/mm2 on 70 μm pixels. Latency of the implant-evoked VEP was at least 30 ms shorter than in response evoked by the visible light, due to lack of phototransduction. Like with the visible light stimulation in normal sighted animals, amplitude of the implant-induced VEP increased logarithmically with peak irradiance and pulse duration. It decreased with increasing frequency similar to the visible light response in the range of 2 - 10 Hz, but decreased slower than the visible light response at 20 - 40 Hz. Modular design of the photovoltaic arrays allows scalability to a large number of pixels, and combined with the ease of implantation, offers a promising approach to restoration of sight in patients blinded by retinal degenerative diseases.

Paper Details

Date Published: 26 February 2013
PDF: 9 pages
Proc. SPIE 8567, Ophthalmic Technologies XXIII, 856709 (26 February 2013); doi: 10.1117/12.2001750
Show Author Affiliations
Yossi Mandel, Stanford Univ. (United States)
George Goetz, Stanford Univ. (United States)
Daniel Lavinsky, Stanford Univ. (United States)
Phil Huie, Stanford Univ. (United States)
Keith Mathieson, Univ. of Strathclyde (United Kingdom)
Lele Wang, Stanford Univ. (United States)
Theodore Kamins, Stanford Univ. (United States)
Richard Manivanh, Stanford Univ. (United States)
James Harris, Stanford Univ. (United States)
Daniel Palanker, Stanford Univ. (United States)

Published in SPIE Proceedings Vol. 8567:
Ophthalmic Technologies XXIII
Fabrice Manns; Per G. Söderberg; Arthur Ho, Editor(s)

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